ML20197D855
| ML20197D855 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 05/09/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20197D838 | List: |
| References | |
| NUDOCS 8605150074 | |
| Download: ML20197D855 (7) | |
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UNITED STATES
-8 NUCLEAR REGULATORY COMMISSION
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p WASHINGTON, D. C. 20555 SAFETY EVALUATION RY THE OF'FICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMEN 0 MENT NO.40 TO FACILITY OPERATING LICENSE NO. NPF-11 COMMONWEALTH EDISON COMPANY LA SALLE COUNTY STATION, UNIT 1 DOCKET NO. 50-373 1.0 INTR 00llCTION By letter from H. Massin, Comonwealth Edison, to H. Denton, NRC, dated October 22, 1985 (Reference 1), Technical Specification chanaes were proposed for the operation of La Salle County Station Unit 1 for Cycle 2 (LSIC2) with a reload using General Electric (GEI manufactured fuel assemblies and GE analyses and methodologies.
Enclosed were the requested Technical Specifi-cation changes and reports (including Reference 2) discussing the reload and analyses done to support and justify the second cycle operation. There was also a subsecuent letter (Reference 3) revising part of the reouested Tech-nical Specification changes relating to single loop operation thermal-hydraulic stability.
2.0 EVALUATION
'2.1 RELOAD DESCRIPTIONS The LSIC2 reload will retain 100 8CR9176 and 432 8CRR219 fuel assemblies from the first cycle and add 232 new BP8CRR799L GE fuel assemblies (about 30% of the fuel).
The reload is based on a Cycle 1 exposure of 10.3 to 10.5 Giga watt days /short ton (GWD/ST1 and a Cycle 2 exposure of 6.8 GWO/ST. The loading will be a conventional scatter pattern with low reactivity fuel on the periphery. This is generally a normal reload with no unusual core i
feature or characteristics. Technical Specification changes are few and primarily related to Maximum Average Planar Linear Heat Generation Rate and i
Minimum Critical Power Ratio (MAPLHGR and MCPR) limits for the new fuel and Cycle 2 core and transient parameters.
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-2.2 FUEL DESIGN The new fuel assembly to be used for LSIC2, BP8CRB299L, was not specifically listed in the latest GESTAR II Revision (Reference 4) or in NRC aoproved amendments at the time of the LSIC2 submittal (Reference 11 Thus the sub-mittal presented a description and information on the assembly usually included in GESTAR II. The assembly is a BP8x8R fuel design, a type aDproved by the NRC, and has been analyzed for this aoplication with the approved methods and meets the aporoved limits discussed in GESTAR II. The fuel enrichment and gadolinium patterns, generally considered a non-safety related change, are acceptable. The BP8CR89.99L assembly has subseouently been included in Amendment 13 to GESTAR II and this section-o# the amendment has been reviewed and approved by the staff.
(Amendment 13.acornval is in final orocessing.) Thus the new fuel is acceptable for LSIC2.
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' 2.3 NUCLEAR DESIGN The nuclear design for LSIC2 has been performed with the methodology described in GESTAR II (Reference 4).
The results of these analyses are given in Reference 2 in standard GESTAR II format. The results are within the range of those usually encountered for RWR reloads.
In particular, the shutdown margin is 1.9 and 1.5% Ak at beginning of. life (BOL) and at the exposure of minimum shutdown margin respectively, thus fully meeting the required 0.38% ok. The Standby Liquid Control System also meets shutdown recuirements with a shutdown margin of 3.8% ok. Since these and other LSIC2 nuclear desion parameters have been obtained with previously aporoved methods and fall within expected ranges, the nuclear desian is acceptable.
2.4 TPERMAL-HYDRAULIC DESIGN The thermal-hydraulic desion for LSIC2 has been performed with the metho-dology described in GESTAR II (Reference 4) and the results are given in Reference 2.
The parameters used for the analyses are those approved in Reference 4 for the la Salle class BWR-5.
The Safety Limit MCPR (SLMCPR) values are increased by 0.01 which is standard when coino from first cycle to reload cores. These SLMCPR values are 1.07 and 1.08 for two and one loop operation, respectively. The Oceratino Limit MCPR (OLMCPR) values are determined by the limiting transients, Dod With-drawal Error (RWE), Feedwater Controller Failure (FWCF) and Load Re,fection Witho.ut Bypass (LRWPP). The analysis of these events for LSIC2, via the 00YN Option B approach, provide new Cycle 2 Technical Specification values of OLMCPR as a function of average scram time, r.
At (and below) a r of 0.736, RWE and FWCF both provide the limit at a MCPR of 1.26.
FWCF is limiting above 0.736 until above a f of 0.755, where LRWBP is the limiting event. Approved methods (Reference 4) were used to analyze these events (and others which could be limitino) and the analyses and results are acceptable and fall within expected ranges.
The changes in MCPR and MAPLHGR limits and scram and rod block setooints on going from two to one (recirculation) loop operation remain the same j
as for Cycle 1.
These changes for one loop operation, which have been determined by approved methods, continue to be acceptable. The Technical Specifications for thermal-hydraulic stability have been chanced and will be discussed later.
It is only the stability aspects of one loop operation which require reaoproval for second cycle one 1000 operation. With the approval of these specifications, one 1000 operation is approved for l
La Salle 1 within the limits given in the relevant Technical Specifications 2.5 TRANSIENT AND ACCIDENT ANALYSES 1
The transient and accident analysis methodolooies used for LSIC2 are described in GESTAR II.(Reference 4).
Generally, the ODYN Option R aporoach was used e
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- for transient analyses. The Loss of Feedwater Heating event was analyzed with the GE RWR Simulator Code, approved in Reference 4.
The limiting MCPR events have been previously indicated in Section 2.4.
The core wide transient analyses methodologies and results are acceptable and fall within expected ranges.
The RWE was analyzed on a plant and cycle specific basis (as opposed to the statistical approach) and a rod block setpoint of 1.07 was selected to pro-vide a OLMCPR of 1.26. The fuel assembly misloading and misorientation events were not analyzed for LSIC2. As approved via Reference 4, the mislocated assembly is not analyzed for reload cores on the basis of studies indicating the small probability of an event exceeding MCPR limits. The misorientation event is not of concern to C lattice cores (i.e. La Salle) because of the symmetry of the fuel bundle, gaps and power distribution.
The local event analyses are thus acceptable.
The limiting p.ressurization event, the Main Steam Isolation valve closure with flux scram, analyzed with standard GESTAR II methods gave results for peak steam dome and vessel pressures well under required limits. These are acceptable methodologies and results.
Loss of coolant accident (LOCA) analyses, usina approved methodologies and parameters (Reference 4), were performed to provide MAPLHGR values for the new reload fuel assemblies (BP8CRRP.90L). These analyses and results are acceptable.
The Rod Droo Accident (RDA) was not specifically anal.yzed for LSIC2.
La Salle uses a Banked Position Withdrawal Sequence for control rod withdrawal.
For plants usina this system the RDA event has been statistically analyzed generically and it was found that with a high degree of confidence the peak fuel enthalpy would not approach the NRC required limit of 280 cal /cm for this event. This app' roach and analysis has been approved by the NRC (Reference a). This approach is acceptable for LSIC2.
I 2.6 THERMAL-HYDRAULIC STABILITY The original submittal. for LSIC2 (Reference 1) presented several chances and. additions to the Technical Specification relating to Thermal-Hydraulic l
Stability (THS) for both two and one (recirculation) loop operation.
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followed a number of discussions with the staff-an the acceptability of these changes for LSIC2. As a result of these discussions, Comonwealt-Edison submitted (Reference 3) a revised approach and new specifications in this area. This review will discuss only the revised approach.
The NRC has recently published two Generic letters (Re'ference 5 and 6) relating to THS. The following is a brief summary of the staff position indicated'in these letters as pertaining in particular to approved GE stability analysis methodoloay and the la Salle reactor characteristics for LSIC2.
1 (1) Aporoved GE analysis methods may be uncertain in the calculation of the THS decay ratio by up to 20%.
(2) Therefore, analyses (for approved fuel) which result in a decay ratio of 0.8 or greater may not be able to comply with General Desion Criteria 10 and 12. Decay ratios well below 0.8 would indicate accept-able stability without further requirements (for two loop operation),
1 but stability calculations would be required for every cycle.
(3) Where further Technical Specification requirements are needed, regions in the power-flow operating map should be defined in which operating restrictions or specific oscillation surveillance and suppression requirements must be met. These regions and surveillance should be consistent with the recommendations of the GE Service Information i
Letter (SIL) - 380 (Reference 7).
(4) For single loop operation (SLO), these types of restrictions and sur-veillance should be institut,ed without specific regard to the decay ratio.
(5) THS Technical Specifications acceptable to the staff have recently been aporoved.
Reference 6 indicates, in particular, that Technical Specifications similar to those approved for Duane Arnold should be submitted.
(6) These Technical Specifications generally call for restrictions or
' surveillance above the 80% rod line (in the power-flow mapl and below 45% flow; surveillance above (aporoximately) 39% flow, no operation below 39%. Surveillance is by observation of the noise level o# the Average Power Range Monitor (APRM) and selected Local Power Ranoe Monitor (LPRM) detectors. Ncise levels greater than 3 times base levels require noise suppression activity, e.g. lower power level.
For LSIC2 the stability has been analyzed using the approved methods (and fuel) of Reference 4.
The result is a decay ratio of 0.60.
- Thus, no increased stability restrictions or surveillance is required for Cycle 2 normal (two loop) operation and Commonwealth Edison has elected to make no Technical Specification changes relating to stability, at this time, for two loop operation. This is acceptable provided that stability analyses are performed for all subseouent cycles and THS technical specifications are implemented when needed.
For SLO, Comonwealth Edison has provided new Technical Specifications in Reference 3 (as changes and additions to 3/4.4.1.1 and Bases).
These changes are in general accord with the specifications approved recently for other reactors (e.g., Duane Arnold). They provide for the establishment of regions above the 80 percent rod line where; (a) below 39% firiw action must be taken to leave the reoion and (b) above 39% flow and below 45% flow action must by taicen to monitor rm r--
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APRM-LPRM noise and to reduce the noise or leave the region if the noise is greater than 3 times the baseline. They also provide for the e
establishment of baseline noise levels when entering the surveillance region (if not previously accomplished in the cycle). These action and surveillance requirements (includina the I.PRM specification) and the times for accomplishing them are comparable to other recently approved specifications and meet the aims of SIL-380. These are acceptable to the staff. Thus, one loop operation is generally accept-able for La Salle without restrictions other than those presented in Specification 3/4.1.1.
2 2.7 TECHNICAL SPECIFICATIONS The Technical Specification changes are for the most part minor and orovide for MCPR and MAPLHGR changes due to second cycle parameter changes and a new fuel assembly, no End of Cycle - Reactor Pump Trip (EOC-RPT) inoperable the one loop operation stability specificatio$. The primary change is for analysis for the cycle, and for a change in k.
The bases for most of these changes have already been discussed. The Specification changes are as follows:
(1) 2.1.2 and Bases and Table B 2.1.2 - 1 thru - 4:
The SLMCPR for two and one (recirculationi loop operations were increased by 0.01 to 1.07 and 1.08.
This is standard practice for second cycles and is based on parameter changes for reload cores aiven in the changes in the Bases Tables. These changes are taken from Reference 4.
These various changes are acceptable.
(2) 3.2.1 and Figures:
j A new MAPLHGR curve is provided for the new fuel and a fuel assembly designation change is made. These are acceptable.
(3) 3.2.3 and Figures:
The EOC-RPT inoperable analyses was not performed for Cycle 2 and thus the provision for this condition was removed. This is acceptable.
The MCPR vs 'C curve is changed to reflect the new transient analyses j
as previously discussed. The change is acceptable.
l The k factor curve was changed to be comoatible with the standard La Safle power and flow values as given in Reference 4.
This is acceptable.
(4) 3.3.4.2; Action d. and e.:
Chances were made to make this specification compatible with the elimination of the EOC-RPT inoperable provision of 3.2.3.
These l
changes, including the indicated power reduction are reasonable and acceptable.
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s (5) 3.4.1.1 and Bases:
These changes are for the Thermal-Hydraulic Stability for single loop operation. They have been discussed in Section ?.6.
They are acceotable.
2.8 REFERENCES
1.
Letter from H. Massin, Commonwealth Edison, to H. Denton, NRC, "LaSalle County Station Unit 1, Proposed Amendment to Technical Specification for Facility Operating License NPF Reload Licensing Package for Cycle 2,"
October 22, 1985 2.
General Electric Report - 23A1843, June 1985, " Supplemental Reload Licensing Submittal -for LaSalle County Station Unit 1, Reload 1 (Cycle 21" 3.
Letter from C. M. Allen, Commonwealth Edison, To H. Denton, NRC,
" Supplemental Information," March 21, 1986 4.
NEDE-24011-A-7, August 1985, " General Electric Standard Application for Reactor Fuel," (GESTAR II) 5.
Generic Letter No. 86-02, " Technical Resolution of Generic Issue B-19-Thermal Hydraulic Stability," January 23, 1986 6.
Generic Letter No. 86-09, " Technical Resolution of Generic Issue No.
B-59-(N-1) Loop Operation in BWRs and PWRs", March 31, 1986
'7.
General Electric Service Information Letter No. 380, Revision 1, February 10, 1984
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation and use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. The staff has determined that this amendment involves no significant increase in the amounts, and no significant change in the types, of any. effluents that may be released offsite, and that there is no significant increase in individual or cumula-tive occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accord-ingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental asses'sment need be prepared in connection with the issuance of this amendment.
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4.0 CONCLUSION
The Commission made a proposed determination that the amendment involves no significant hazards consideration which was initially published in the Federal Register (50 FR 478591 on November 20, 1985, and a renotice which was published in the Federal Register (51 FR 12225) on April 9,1986. No public comments were received on either notice, and the state of Illinois did not have any comments.
We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regula-tions and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
H. Richings, NRR Dated:
May 9, 1986 a
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